Glass pressure measuring apparatus

ABSTRACT

AN ALL GLASS PRESSURE MEASURING DEVICE FOR INDICATING PRESSURE BUILDUP OF CERTAIN MATERIALS UNDER PREDETERMINED ENVIRONMENT CONDITIONS WHICH COMPRISES A CLOSED GLASS SAMPLE CYLINDER HAVING A BOURDON GUAGE AND A FILL TUBE SEALED TO THE TOP THEREOF. A GLASS HOUSING OPEN AT ONE END IS SEALED TO THE TOP SO AS TO SURROUND SAID FILL TUBE AND BOURDON GUAGE. A SMALL MIRROR IS ATTACHED TO THE CLOSED END OF THE BOURDON TUBE GUAGE AND ANOTHER MIRROR IS ATTACHED TO THE OUTSIDE OF THE HOUSING WHICH ACTS AS A REFERENCE MIRROR. A CHANGE IN PRESSURE CAUSES THE MIRROR ON THE BOURDON GUAGE TO FLASH A BEAM OF LIGHT WHICH IS RECORDED FROM A SCALE ON A MEASURING APPARATUS.

United States Patent [72] Inventors Denali-Celeb;

George W. Bardette, China Lake, Calif. [2]] Appl. No. 886,229

Primary Examiner-Donald O. Woodie] Attorneys-R. S. Sciascia and RoyMiller ABSTRACT: An all glass pressure measuring device for indicatingpressure buildup of certain materials under predetermined environmentalconditions which comprises a closed glass sample cylinder having aBourdon gauge and a fill tube sealed to the top thereof. A glas housingopen at one end is sealed to the top so as to surround said fill tubeand Bourdon gauge. A small mirror is attached to the closed end of theBourdon tube gauge and another mirror is attached to the outside of thehousing which acts as a reference mirror. A change in pressure causesthe mirror on the Bourdon gauge to flash a beam of light which isrecorded from a scale on a measuring apparatus.

PATENTEH JUN28 IH'ZI SHEET 1 BF 2 INVENTORS GLASS PRESSURE MEASURINGAPPARATUS GOVERNMENT INTEREST The invention described herein may bemanufactured and used by or for the Government of the United States ofAmerice for governmental purposes without the payment of any royaltiesthereon or therefor.

BACKGROUND OF THE INVENTION This invention relates to an all glasspressure measuring device.

For measuring pressure exerted by gases or vapors as in boilers, airtanks, etc., the well-known manometer is generally used. Multimetalsystems are also used, but these devices are often plagued with leaks.The present invention provides a positively sealed system which is allglass thereby eliminating unnecessary compatibility problems such asmercury and dissimilar metals. It is therefore the general object ofthis invention to provide a pressure measuring device which is simpleand easy to construct and the result can be visually observed.

DESCRIPTION OF THE DRAWING FIG. I is. an isometric of the presentinvention;

FIG. 2 is a section taken through 2-2 of FIG. 1;

FIG. 3 is a section showing another embodiment; and FIG. 4 is aschematic illustrating the mode of operation of the invention.

DESCRIPTION OF THE INVENTION Referring now to the drawing there is shownin FIG. 1 the pressure. measuring device 10. which comprises a hollowglass cylinder 12, closed at the top. and bottom, about 50 mm. indiameter and. of any desired length. A hollow fill: tube 14 is torchsealed to32edgesof an. aperture 13 provided in the top of cylinder 12.so as. to. communicate with the interior of cylinder I2 for filling;purposes. A glass Bourdongauge I6 is torch sealed. at, its open. end to.the edges of asecond aperture 17 provided in cylinder lllwhichcommunicates with. the interior of said cylinder. A glass housing 18 issecured by torch sealing on other suitable means to the outer wall ofcylinder 12 soas to surroundlon guard; Bourdongauge l6 and'fill'tube 14.Housing 18 is open. at. the: top. Bourdon tube gauge 16 is closed. at;oneend' with. a. solidcurved; glass tip 20 on which a first'mirron22issecuredibytorchtseal, cement, or other suitable'means.Amopeniwindow.M'isprovided'in the-wall of housing;18;oppositesaid1mirror 22 to permit uninterrupted 'reflection of: lightfrom.mirror. 22..A- second'mirror 26vis positioned at the-bottom'of window24- so that the'topof mirror 26 is in substantialalignment withthebottom offirst mirror 22. Window. 24 permits thepassageof' light fromfirst'mirror 22 thus minimizing aberration. In operation the pressuredevice iscalibrated by. meansof a laser. pressure-reading apparatus 30as shown. in Flfic4since manufacture of the glass- Bourdon gauges is:not yet'standardized: Cylinder; or container: 12 is filled-throughtubel4 which:isthen:torch sealed. atpoint Device 10is-placed'inthedesired testenvironmenvandatintervals broughtinto thelaboratory and'the'temperature read; Generally,the-pressure is ,read; at25'C. As shown in FlG. 4 pressure reading apparatus30"providedcomprising'abase-32, a laser; 34*mountedon stand'36'1whichispositionedabout'midway. on'said-base 34$ Neanoneend'zofbase-34'amillimeter scale-38 is mounted Iupright and *atrtheother end aholder 405is positioned-towhich said pressure measuring deviceis=suitably secured. In =calibrating thezdevicelasenbeamaM is directedto and spl-iti by. second mirror:26?( reference and first I mirrorr22(movable): The lower half of split beam designated 46is reflected frommirrorp26 to scale. 38=as-a zero =or=reference point:The'uppervparhofithesplit beam designated '47 from mirror '22., isreflected also onto scale 38=and moves upward as pressure, increasessincyIinder'I-Z. creating astraighteninge effect-on the.;Bourdon-.-gauge;Theareading-difference between the reference beam 46 "and-the Bourdongauge. light beam 47 is then made and the pressure calculated. Thedegree of movement of the Bourdon gauge is proportional to the appliedpressure. The glass Bourdon gauge also acts as a safety release becauseit will break at pressures slightly above the design value of 50p.s.i.g.

In another embodiment shown-in FIG. 3 a hollow breakoff seal 17 forsample or gas removal from cylinder 12 is torch sealed to a thirdaperture 21 positioned on the top of cylinder 12 or may be positioned oncylinder 12 above the level of the material contained therein. Itprovides a simple means for quick and easy removal of gas or materialfor test purpose. Also, as shown in FIG. 3, mirror 26 can be affixed toa solid glass rod 19 which is torch sealed to the dome or top ofcylinder l2 and positioned so as to permit the light beam to passunimpeded through window 24 in housing 18. Rod 19 provides a firmattachment for mirror 26 and thereby avoids movement of the mirror whichmay occur under certain environmental conditions; particularly if themirror is cemented to housing 18. In this embodiment housing 18 was madeof optically clear plastic and clamped to the outside of cylinder 12thereby effectively protecting the dome of said cylinder.

The Bourdon gauge is commercially available for the measurement ofliquid or gas pressure. It consists of a curved tube of elliptical crosssection. One end of the tube is closed and the application of pressureto the other end causes the curvature to be reduced slightly, and theindicator to be operated. Over a certain range, the degree of movementobtained is proportional to the applied pressure.

The present invention can be positively sealed and the sealed fillingtube can be broken off inside a piece of plastic tubing so the totalsample, gases, and liquid can be transferred toanalyses equipment. Thepreferred material for all the components of this device is glass sothat the sample along with any reaction can be visually observed. Thisdevice can be easily handled in' an inert and/or anhydrous atmosphere.

The herein described pressure measuring device can be constructed ofmost any type'glass desired and the size can be altered to suit the testbeing run. Some of the advantages of this device are (l) the vessel isall glass, thus eliminating unnecessary compatibilityproblems with suchthings as mercury and dissimilar metals; (2) the apparatus is torchsealed, thereby eliminating any possibility of leaks; (3) the apparatusis much cheaper to construct than others on the market; and

ingcorrosion rates, stress corrosion, tensilesamples, welding effects,surface area effects, dissimilar metals, compatibilityand-storage-seating tests.

We claim:

I. Anall glass-pressure measuring dcvicecomprising a-hollow cylinderclosed at each'en'dandhaving a first aperturepositioned near the centerof the front end of said cylinder, and a second aperture positioned'nextto said first aperture;

a Bourdon gauge'having its open end sealed to the edges ofsaidfirst'aperture'so as to'communicate with the interior of saidcylinder;

a filling tube'having one end sealed to the edges of said secondaperture so as to communicate with the interior of said cylinder;

afirstmirror secured 'tothe solid tip of saidBourdon'gauge whereby lightis reflected with any movement of said Bourdongauge;

a cylindrical housing open at both ends having one' end sealedtothewalls of thefront end of said cylinder so'as to guard said fillingtube and said Bourdon gauge; said housing'having-an open windowpositioned opposite said first minor;

a second mirror secured to the base-ofsaid window sothat the top edge ofsaid second mirroris substantially in alignment'with the bottom'edge ofsaidfirst'mirror, whereby a light beamreflected fromsaid second mirroris used as a zero reference with'respectto said light beam'reflectedsecond mirror is secured to a solid glass rod firmly secured to the topof said cylinder.

4. The device in accordance with claim I wherein said housing consistsessentially of optically clear plastic and is clamped onto the outsideof said cylinder.

